Batteries play an important role in any mechanism that does not operate from the mains. Rechargeable batteries are quite expensive due to the fact that you need to purchase a charger along with them. Batteries use different combinations of conductor materials and electrolytes - lead-acid, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), lithium-ion (Li-ion), lithium-ion polymer (Li-Po).
I use lithium-ion batteries in my projects, so I decided to make my own charger for 18650 lithium batteries rather than buy an expensive one, so let's get started.
Step 1: Video
The video shows the assembly of the charger.
Link to youtube
Step 2: List of Electrical Components
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List of components required to assemble a 18650 battery charger:
- Charger module based on TP4056 chip with battery protection
- Voltage stabilizer 7805, you will need 1 piece
- Capacitor 100 nF, 4 pcs (not needed if there is a 5V power supply)
Step 3: List of Tools
To work you will need the following tools:
- hot knife
- Plastic box 8x7x3 cm (or similar in size)
Now that all the necessary tools and components are prepared for work, let's move on to the TP4056 module.
Step 4: Li-io battery charger module based on TP4056 chip
A little more about this module. There are two versions of these modules on the market: with and without battery protection.
The circuit board containing the protection circuit monitors the voltage using the power circuit filter DW01A (battery protection integrated circuit) and FS8205A (N-channel transistor module). Thus, the breakout board contains three integrated circuits (TP4056+DW01A+FS8205A), while the charger module without battery protection contains only one integrated circuit (TP4056).
TP4056 – charge module for single-cell Li-io batteries with linear charge of constant current and voltage. The SOP housing and low number of external components make this module an excellent option for use in homemade electrical appliances. It charges via USB just as well as a regular power bank. The pinout of the TP4056 module is attached (Fig. 2), as is the charging cycle graph (Fig. 3) with constant current and constant voltage curves. Two diodes on the switching board indicate the current charging status - charging, charging stopped, etc. (Fig. 4).
To avoid damaging the battery, charge 3.7V lithium-ion batteries at 0.2-0.7 DC current until the output voltage reaches 4.2V, after which the charge will be constant voltage and gradually decreasing (up to 10% of the initial value) current. We cannot interrupt the charge at 4.2 V, since the charge level will be 40-80% of the battery's full capacity. The TP4056 module is responsible for this process. Another important point is that the resistor connected to the PROG pin determines the charging current. In modules on the market, a 1.2 KΩ resistor is usually connected to this pin, which corresponds to a charging current of 1A (Fig. 5). To get other charging current values, you can try using other resistors.
DW01A is a battery protection integrated circuit, Fig. 6 shows a typical connection diagram. MOSFETs M1 and M2 are connected externally by an FS8205A integrated circuit.
These components are installed on the breakout board of the TP4056 lithium-ion battery charger module, which is linked in Step 2. We only need to do two things: give a voltage in the range of 4-8 V to the input connector, and connect the battery poles with both the + and - pins. module TP4056.
After this, we will continue assembling the charger.
Step 5: Wiring Diagram
To complete the assembly of electrical components, we solder them in accordance with the diagram. I have attached a diagram in Fritzing software and a photo of the physical connection.
- + connect the power connector contact to one of the switch contacts, and – connect the power connector contact to the GND pin of the 7805 stabilizer
- We connect the second contact of the switch to the Vin pin of the stabilizer 7805
- We install three 100 nF capacitors in parallel between the Vin and GND pins of the voltage regulator (use a breadboard for this)
- Install a 100 nF capacitor between the Vout and GND pins of the voltage regulator (on the breadboard)
- Connect the Vout pin of the voltage regulator to the IN+ pin of the TP4056 module
- Connect the GND pin of the voltage regulator to the IN pin of the TP4056 module
- Connect the + contact of the battery compartment to the B+ pin of the TP4056 module, and connect the – contact of the battery compartment to the B- pin of the TP4056 module
This completes the connections. If you are using a 5V power supply, skip all the points with connections to the 7805 voltage regulator, and connect the + and – of the unit directly to the IN+ and IN- pins of the TP4056 module, respectively.
If you use a 12V power supply, the 7805 stabilizer will heat up when a 1A current passes, this can be corrected with a heat sink.
Step 6: Assembly, part 1: cutting holes in the body
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In order to correctly fit all the electrical components in the housing, you need to cut holes in it:
- Using a knife blade, mark the boundaries of the battery compartment on the case (Fig. 1).
- Use a hot knife to cut a hole according to the marks made (Fig. 2 and 3).
- After cutting the hole, the housing should look like in Fig. 4.
- Mark the place where the USB connector of the TP4056 module will be located (Fig. 5 and 6).
- Using a hot knife, cut a hole in the case for the USB connector (Fig. 7).
- Mark the places on the case where the diodes of the TP4056 module will be located (Fig. 8 and 9).
- Use a hot knife to cut holes for the diodes (Fig. 10).
- In the same way, make holes for the power connector and switch (Fig. 11 and 12)
Step 7: Assembly, part 2: installing electrical components
Follow the instructions to install components in the chassis:
- Install the battery compartment so that the mounting points are on the outside of the compartment/case. Glue the compartment with a glue gun (Fig. 1).
- Replace the TP4056 module so that the USB connector and diodes fit into the corresponding holes, secure with hot glue (Fig. 2).
- Replace the voltage stabilizer 7805 and secure it with hot glue (Fig. 3).
- Reinstall the power connector and switch and secure them with hot glue (Fig. 4).
- The location of the components should look the same as in Fig. 5.
- Secure the bottom cover in place with screws (Fig. 6).
- Later I covered the rough edges left by the hot knife with black electrical tape. They can also be smoothed with sandpaper.
The completed charger is shown in Figure 7. now it needs to be tested.
Step 8: Test
Place the discharged battery in the charger. Turn on the power to the 12V or USB connector. The red diode should blink, this means that the charging process is in progress.
When the charge is complete, the blue diode should light up.
I am attaching a photo of the charger during charging and a photo with a charged battery.
This completes the work.
Many people probably have a problem with charging a Li-Ion battery without a controller; I had this situation. I received a dead laptop, and there were 4 SANYO UR18650A cans in the battery that were alive.
I decided to replace the LED flashlight with three AAA batteries. The question arose about charging them.
After digging around on the Internet I found a bunch of diagrams, but details are a little tight in our city.
I tried charging from a cell phone charger, the problem is in charge control, you need to constantly monitor the heating, it just starts to heat up, you need to disconnect from charging, otherwise the battery will be damaged in the best case, otherwise you can start a fire.
I decided to do it myself. I bought a bed for the battery in the store. I bought a charger at a flea market. To make it easier to track the end of the charge, it is advisable to find one with a two-color LED that signals the end of the charge. It switches from red to green when charging is complete.
But you can also use a regular one. The charger can be replaced with a USB cord and charged from a computer or charger with a USB output.
My charger is only for batteries without a controller. I took the controller from an old cell phone battery. It ensures that the battery is not overcharged above a voltage of 4.2 V, or discharged below 2...3 V. Also, the protection circuit saves from short circuits by disconnecting the bank itself from the consumer at the moment of a short circuit.
It contains the DW01 chip and an assembly of two SM8502A MOSFET transistors (M1, M2). There are also other markings, but the circuits are similar to this one and work similarly.
Cell phone battery charge controller.
Controller circuit.
Another controller circuit.
The main thing is not to confuse the polarity of soldering the controller to the bed and the controller to the charger. The controller board has “+” and “-” contacts.
It is advisable to make a clearly visible indicator in the bed near the positive contact, using red paint or self-adhesive film, to avoid polarity reversal.
I put everything together and this is what happened.
Charges great. When the voltage reaches 4.2 volts, the controller disconnects the battery from charging and the LED switches from red to green. Charging is complete. You can charge other Li-Ion batteries, just use a different bed. Good luck to all.
Almost all modern lithium-ion batteries have excellent energy capacity, as well as high compact dimensions. It is with their help that you can power high-power devices with the greatest efficiency. And for this it is absolutely not necessary to buy a ready-made charger in a store, because there is a more budget-friendly option that radio amateurs will especially like - to assemble a charger for lithium-ion batteries with your own hands.
Precautions: overcharging is prohibited
It is extremely important to remember one simple thing before starting to assemble a battery for batteries - lithium batteries are strictly prohibited from recharging. They have very strict requirements for the charging mode and operation, so they cannot be charged to a voltage greater than 4.2 V. It is even better to be guided by information about the safe threshold for each individual can. By the way, even a lower threshold may be indicated there, which is considered acceptable for this instance.
It’s even better if you’re going to do your own lithium battery charging, check the materials and equipment used several times. If you have doubts about the accuracy of your voltmeter readings or the origin of the cans, as well as the maximum permissible power of their charge, it is better to set the threshold even lower. The optimal range will be within 4.1–4.15 V. In this case, charging batteries that do not have a built-in protection board will be safe for you.
Otherwise, there is a high probability of strong heating and swelling of the cans, copious release of gas with a strong unpleasant odor, and even their subsequent explosion. Check everything several times before proceeding with assembly and charging.
How to assemble a lithium charger DIY batteries
One of the simplest, if not the simplest, option for creating a charger. It involves the use of the LM317 chip. It is cheap and widely available, plus it is equipped with a charge indicator.
The setup comes down to setting the output voltage to 4.2 Volts using trimming resistor R8. Just be sure to not have the battery connected. The charging current is also set by selecting resistors R4 and R6. The recommended power of resistor R1 should be at least 1 Watt.
When the LED on the circuit goes out, this signals the completion of the battery charging process. In this case, the charging current will never decrease to zero.
Microcircuits of the LM317 type, like its analogues, are very widely used in all kinds of current and voltage stabilizers. At the same time, you can buy them at any radio market, and they will cost mere pennies.
The disadvantage of the circuit can be considered the supply voltage, which must be from 8 to 12 V. This is due to the fact that for the normal functioning of the microcircuit, a difference between the voltage on the automatic transmission and the supply voltage is required to be at least 4.25 V, that is, power the device using the USB port will not work.
The sequence for collecting lithium battery charging with your own hands is as follows:
- select a suitable case;
- attach the power supply (5 V) and the elements of the specified circuit to it (necessarily in the correct order);
- take brass and cut out two strips from it, attach them to the sockets;
- using a nut, set the distance between the contacts and the battery that you are going to connect;
- attach the switch if you want to later be able to change the polarity on the sockets (if not, leave everything as is).
But if the task is to assemble a charger designed to work with 18650 batteries, then you should immediately move on to more complex circuits, or buy a ready-made device. Without the appropriate technical skills, it will not be possible to assemble the unit. Sometimes it’s really easier to spend a little more money, but take a factory charger with the necessary parameters and protection.
How to assemble a charger for lithium-ion batteries with your own hands?
Since Li-Ion batteries are sensitive to sudden voltage during charging, special chips are built into branded batteries. They provide voltage control and do not allow the permissible limits to be exceeded. Therefore, in order to assemble a charger for 18650 lithium batteries with your own hands, you need a more complex circuit than the one discussed above.
This version of the battery will be much more difficult to create than the previous one, and at home it is only possible if you have certain skills and relevant experience. In theory, you can get a charger whose characteristics are in no way inferior to branded batteries. But in practice this is not always the case.
Have you assembled a charger at home from scrap materials? Tell us about your results in the comments.
Many may say that for little money you can order a special board from China, through which you can charge lithium batteries via USB. It will cost about 1 dollar.
But there is no point in buying something that can be easily assembled in a few minutes. Do not forget that you will have to wait about a month for the ordered board. And a purchased device does not bring as much pleasure as a home-made one.
Initially it was planned to assemble a charger based on the LM317 chip.
But then to power this charge, a higher voltage than 5 V will be required. The chip must have a 2 V difference between the input and output voltages. A charged lithium battery has a voltage of 4.2 V. This does not meet the described requirements (5-4.2 = 0.8), so you need to look for another solution.
Almost everyone can repeat the exercise that will be discussed in this article. Its scheme is quite simple to repeat.
One of these programs can be downloaded at the end of the article.
To more accurately adjust the output voltage, you can change resistor R2 to a multi-turn one. Its resistance should be about 10 kOhm.
Attached files: :
How to make a simple Power Bank with your own hands: diagram of a homemade power bank Do-it-yourself lithium-ion battery: how to charge correctly
Detailed description of 18650 lithium-ion batteries, making a charging device with your own hands, nuances of application.
TEST:
To see if you have enough information about your lithium-ion battery:- What was the main disadvantage of the first 18650 battery models?
a) They exploded due to lithium metal inside - with frequent charging, accumulations appeared on the element, leading to an explosion.
b) The battery was too bulky and inconvenient.
- What problem have the manufacturers of modern 18650 models not yet gotten rid of?
a) The battery often overheats.
b) The battery quickly loses charge when exposed to negative temperatures.
- In what temperature range is it desirable to store the battery?
a) + 10 – + 25 – ideal indicators. The battery does not tolerate extremely cold or hot rooms.
b) Store the battery at low temperatures when not in use.
c) At a temperature of +30-45 degrees.
- Why can't I buy a charger made in China?
a) The case is too unreliable.
b) Low quality parts, correct assembly technology is not always followed.
- At what charge level is it advisable to store the battery?
a) The 18650 should be stored at a charge level that does not fall below 50%. A complete discharge cannot be performed.
b) Not lower than 10%.
Answers:
- a) The main disadvantage of the first models is the risk of explosion. Lithium metal grew overgrown with frequent charging and a short circuit occurred, leading to an explosion of the battery.
- b) Modern batteries do not tolerate low temperatures well - the charge drops very quickly.
- a) + 10 – + 25 – ideal indicators. Do not place the battery in other conditions.
- b) Chinese manufacturers often use low-quality parts when assembling devices, so they fail. The correct assembly technology is not always followed.
- a) If you plan to keep the battery idle for a long time, then make sure that the charge on it does not fall below 50%, otherwise the battery will deteriorate.
Owners of lithium-ion batteries The 18650 faces the question of what current to charge it with. There are also difficulties with proper operation; people do not know exactly what such batteries are afraid of, or how to increase their operating time.
To assemble an electronic cigarette or flashlight yourself, you must study all aspects work with lithium-ion power supply.
Definition: Li-ion battery is an electric current battery that has become widespread among consumer electronics since 1991. It was this year that Sony Corporation presented the product to the wider market.
Answers to 5 Frequently Asked Questions
- What are lithium-ion batteries used for?
- As a power source. Such batteries are often used for various mobile phones, video cameras, laptops, for recharging electric vehicles or modern electronic cigarettes.
- Do the models have any disadvantages?
— The main drawback of the model was that the first developments literally exploded. This is explained by the fact that manufacturers placed an anode consisting of lithium metal inside. When a large number of charges and discharges occur, formations appear on the anode, leading to the short circuit of the electrodes. As a result, a fire occurs, and then an explosion. This problem has now been resolved.
- How was the problem with explosions solved?
— To make the structure safer, scientists replaced the core with graphite, and got rid of the problem with explosions. But there were still difficulties with the cathode caused by the cobalt oxide design. If the operational characteristics were violated, the explosions were repeated. That is why it was necessary to ensure that the device was not overcharged. It was extremely inconvenient for users to constantly monitor the charge level and the developers had to modify the device again. Modern models are safe. When developers began using lithium ferrophosphate batteries, they managed to get rid of this problem. Modern devices are manufactured in such a way that overcharging and overheating are impossible.
- Do modern models have disadvantages?
— The charge is lost if the battery is exposed to low temperatures.
- If you don't use the battery for a long time, will it deteriorate?
– If you do not lower the rarefaction level below 50%, it will not deteriorate.
3 benefits of battery
Lithium-ion batteries have a number of positive aspects, which is why they gained popularity:
- Extra large capacity battery
- Small self-discharge
- No special maintenance required.
Charging – 5 nuances
Charger Look at the picture of the original charger device. The charger designed for lithium-ion batteries is very similar to the lead-acid type of battery. The difference is that lithium-ion battery There are high voltages on each bank and severe voltage tolerance requirements.
This is interesting! The battery is called a “can” because of its similarity to the aluminum cans used for soft drinks.
"Banks" Most Popular Items nutrition with this form - 18650. The battery received this name because of its dimensions: diameter - 18 mm, height - 65 mm. When charging lead-acid batteries batteries, Minor inaccuracies in voltage indications are allowed. But with lithium-ion devices, everything is much more specific. When it happens charger, and the voltage increases to 4.2 Volts, the voltage to the element must be stopped immediately. The error is only 0.5 Volts.
Chinese exercise There are a large number of Chinese chargers designed for batteries of different materials. Without compromising performance, ion batteries are charged with a current of 0.8 A. But the voltage in the bank will have to be very strictly controlled. When the value is 4.2 Volts, immediately stop charging. But in the event that it is built into the jar controller, then you don’t have to worry about it, because the device will do everything on its own.
Chargers 4.2 Volt
As charger For a lithium-ion battery, a voltage stabilizer is used, limiting the current at the very beginning of charging. It is necessary to use an extremely stable voltage and limit the current at the very beginning of the charging process. Charging should be completed at the moment when the stable voltage is 4.2 Volts, absent current, or its value is very small - around 5-7 mA.
Oxidation When a battery rod is placed in graphite, then the voltage should not exceed 4.1 V per element. If this rule is neglected, the energy density will increase greatly and oxidation processes of the device will begin. As a result, the battery will fail. To avoid oxidation, modern models are equipped with additives - graphite in its pure form there is no inside. But similar models can still be found by chance.
How to properly charge Li-ion batteries. Parallel connection of batteries.
Homemade charger at home (with your own hands) - 1 circuit
For charging 18650 purchase a universal charger and constantly use a multimeter to find out the necessary parameters. But such a device is quite expensive. Minimum price – 2700 rubles.
Instead, you can spend just a few hours and assemble a charger device on one's own. The advantages of this assembly are low cost, reliability, and automatic battery shutdown. All the parts used for assembly can be found in any radio amateur's garage. If something is missing, you can buy it at the nearest radio store. You will have to spend a maximum of 300 rubles on components.
If diagram If assembled correctly, there is no need for additional configuration - it will be immediately ready for use.
You need to use the following electrical diagram:
Scheme
The positive thing is that if you install stabilizer to the desired radiator, then the battery is charged without fear that the charger will catch fire. But this certainly cannot be said about Chinese chargers, which suffer from this unpleasant consequence.
Operating principle – 4 nuances
- to start battery must be charged using direct current, which is determined by the resistance of resistor R4;
- after battery receives a voltage of 4.2 Volts, the device switches to DC charging;
- when the current drops to minimum values, the LED will stop lighting;
- current recharging lithium-ion battery, should not exceed 10% of the capacity of the entire battery. Thus, the service life of the batteries increases. If resistor R4 has a value of 11 ohms, then the circuit current should be 100 mA. If the resistance is 5 ohms, then the charging current should be 230 mA.
It is also important to know 3 nuances about “life extension” 18650
- If battery will need to be left unused for some time, it is advisable to store the batteries separately from the device that they will power. If a cell is fully charged, it will lose some of its charge over time. In the case when the element is charged very little, or is completely discharged, its performance may completely disappear. This is especially noticeable during periods of long hibernation.
- Storage 18650 should be carried out at a charge level that does not fall below 50%. Under no circumstances should the cell be allowed to be fully charged or overcharged. This equipment has no memory effect. Charging must be done until the charge is completely exhausted. This will extend the battery life.
- Battery Do not leave in too cold or hot rooms. Suitable storage temperature is + 10 - + 25 degrees Celsius. If you place the battery in the cold, not only will the operating time decrease, but the chemical system will also deteriorate. Everyone has probably noticed that when using a mobile phone in winter, the charge batteries falls sharply.
How to avoid 4 mistakes when using and charging a lithium-ion battery
- In the event that you decide to recharge the lithium-ion battery using a store charger, you will have to make sure that it is not made in China. Typically, such devices are assembled from the cheapest materials, and the required technology is not always observed in them. As a result, this can lead to very sad consequences: fire and explosion.
- If you want to assemble it yourself device, then to charge the battery you need to use a current that is 10% of the battery capacity. The percentage may be higher, but not exceed 20%.
- When using ion batteries, do not violate the rules of storage and operation, otherwise overheating, fire and explosion may occur.
- If you follow all the rules operation, as well as the correct storage conditions, the battery life will be extended.
Top 3 Best Chargers for 18650 Battery
To ensure high-quality battery charging, you should purchase good devices, which is already loved by many users.
- Nitecore Digicharger D4 – suitable for charging multiple batteries at once. Extremely easy to use.
- Nitecore i2 is one of the best options for modern devices. Clear and easy to use.
- Basen B21 is a universal device for different types of batteries.
